What type of copper pipe can be used under ground, i.e. either Y or Z

What type of copper pipe can be used under ground, ie either Y or Z
Hey Chuck,
Point me to where I can purchase type "Z" copper.
Copper pipe is available in three basic types: Type M is thin-walled, Type L is medium-walled and Type K is thick-walled. In most cases, Type L is good for home and underground use. Check your city code to determine which type of pipe is required for the work you're planning.
Good luck, Tom PS. It's not a good idea to use your last name in the internet.

Hey Charlie:

In my area, only type K copper is allowed underground.

As Tom said.. check with local codes enforcement... good luck... MARK